77121408 has 128 divisors (see below), whose sum is σ = 252241920. Its totient is φ = 20330496.

The previous prime is 77121391. The next prime is 77121419. The reversal of 77121408 is 80412177.

It is a tau number, because it is divible by the number of its divisors (128).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 33841 + ... + 36047.

It is an arithmetic number, because the mean of its divisors is an integer number (1970640).

Almost surely, 2^77121408 is an apocalyptic number.

77121408 is a gapful number since it is divisible by the number (78) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 77121408, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (126120960).

77121408 is an abundant number, since it is smaller than the sum of its proper divisors (175120512).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

77121408 is a wasteful number, since it uses less digits than its factorization.

77121408 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2244 (or 2232 counting only the distinct ones).

The product of its (nonzero) digits is 3136, while the sum is 30.

The square root of 77121408 is about 8781.8795254774. The cubic root of 77121408 is about 425.6555658884.

The spelling of 77121408 in words is "seventy-seven million, one hundred twenty-one thousand, four hundred eight".